Image: Scientists found that by testing for 19 new genetic factors in addition to the 25 risk genes already known, they could identify the 1% of men at highest risk of testicular cancer (Photo courtesy of Shutterstock).
Results of a large genome-wide association study (GWAS) have enabled the identification of 19 new risk loci and potential regulatory mechanisms influencing the susceptibility to testicular germ cell cancer.
Genome-wide association studies have transformed understanding of susceptibility to testicular germ cell tumors (TGCTs), but much of the heritability has remained unexplained. To clarify this topic, investigators at The Institute of Cancer Research, London (United Kingdom) conducted a new GWAS - a meta-analysis combined with previous GWAS and a replication series, totaling 7,319 TGCT cases and 23,082 controls.
The investigators reported the identification of 19 new TGCT risk loci, roughly doubling the number of known TGCT risk loci to 44. By performing in situ Hi-C (a chromosome conformation capture technique) in TGCT cells, they provided evidence for a network of physical interactions among all 44 TGCT risk SNPs (single-nucleotide polymorphism) and candidate causal genes.
These results allowed the investigators to select the 1% of men at highest risk of developing the disease. These men had a 7% lifetime risk of developing testicular cancer - a risk 14 times higher than the 0.5% risk in the general male population.
Senior author Dr. Clare Turnbull, senior researcher in genetics and epidemiology at The Institute of Cancer Research, London, said, "Our study has almost doubled the number of DNA variations linked to increased risk of developing testicular cancer and advanced our ability to use genetics to predict disease in healthy men. Although we are making good headway, there are more genetic changes that affect risk still to be found. Further studies are needed to understand how these genetic changes interact over time to influence the biology of the cell and lead to development of cancer."
The study was published in the June 12, 2017, online edition of the journal Nature Genetics.
The Institute of Cancer Research